2-aminolicosanedioic acids

ABSTRACT

2-Aminoeicosansdiaic acids of the formula   WHEREIN N IS 7 OR 8, AND R1 and R2 are hydrogen or lower alkyl, are readily prepared by Strecker reaction and hydrolysis from the mixture of methyl 9-formylstearate and methyl 10-formylstearate which results from hydroformylation of methyl oleate, and is referred to hereinafter as methyl 9(10)-formylstearate. The aqueous neutral or alkaline solutions of the acids have excellent detergent properties.

United States atent Wakamatsu et al.

Z-AMINOLICOSANEDIOIC AClDS Appl. No.: 15,873

Foreign Application Priority Data March 14, 1969 Japan ..44/ 19349 US. Cl. ..260/534 E, 252/ 1 l0, 252/1 17, 252/356, 260/3095, 260/4045, 260/4109, 260/482 P, 424/313, 424/319 Int. Cl ..C07c 101/20 Field of Search ..260/534 E, 482 D References Cited UNITED STATES PATENTS 6/1940 Ulrich ..260/534 E 10/1958 Singer et al. ..260/534 E 9/1946 Bersworth ..260/534 E 5/1956 Moury et al ..260/534 E 1/1966 Morris et al ..260/534 E [151 3,683,19 5] Aug.8,1972

FOREIGN PATENTS OR APPLICATIONS 37/5907 6/ 1962 Japan ..260/5 34 G Primary Examiner-Lorraine A. Weinberger Assistant Examiner-John F. Terapane AttorneyKelman and Berman ABSTRACT Z-Aminoeicosansdiaic acids of the formula CNH GOOH

wherein n is 7 or 8, and R and R are hydrogen or lower alkyl, are readily prepared by Strecker reaction and hydrolysis from the mixture of methyl 9-formylstearate and methyl lO-formylstearate which results from hydroforrnylation of methyl oleate, and is referred to hereinafter as methyl 9( l0)-formylstearate. The aqueous neutral or alkaline solutions of the acids have excellent detergent properties.

2 Claims, No Drawings Z-AMINOLICOSANEDIOIC ACIDS This invention relates to the novel 2-aminoeicosandioic acids of the formula:

COOH

(wherein n is 7 or 8; and R and R are hydrogen or lower alkyl), and relates to a method of preparing them, and to their use as detergents.

The compounds consist of a hydrophobic long chain alkyl group and three functional groups, which gives them surface-active and polymerization ability, and they can be modified by converging the functional groups to other suitable ones.

It has been found that 2-aminoeicosanedicarboxylic acids have the following properties:

1. Their surface-activity in a neutral or alkaline solution is high and the foaming tendency is low. They are soluble in a concentrated aqueous solution of inorganic salts, without being salted-out. For instance, they have stable surface-activity even in a 60 wt. percent aqueous solution of inorganic salts. They do not produce a precipitate with proteins, particularly in a neutral or alkaline aqueous solution. The detergency, particularly in hard water is high.

3. They are stable against heat, acid or alkali in solution and in the solid state.

4. The chelating ability is high. For example, they readily form a copper salt.

5. The solubility in water is great under neutral and alkaline conditions and they give an aqueous solution of more than 20 wt.% concentration. The Krafft point is low.

6. The dispersing and emulsifying powers for fine particles, such as carbon-black, clay, dirt, dirty oil and the like are great.

7. They do not irritate the human skin and mucous membranes.

8. They have a strong affinity for the surfaces of metal, protein and the like.

9. Enzymes, such as protease, amylase and lipase, are

not significantly hardly inactivated by the compounds. Therefore, enzymatic cleaning materials containing the compounds of this invention as a main component retain their enzyme activity for prolonged periods.

Therefore, the compounds, their ammonium, alkali metal, other metal salts or their mono esters are useful in the textile, dyeing, plastic, tanning, paints, printing, food, cosmetics and metal industries. A compound of the invention may be used as a detergent agent, a rust inhibitor, an antistatic agent, an antifoaming agent, a collector, an emulsifying agent, a fuel additive, a lubricant, an oil additive and an antioxidant, also as a germicide.

According to the present invention, the compounds are produced in a high yield from 9( lO)-formylstearic acid or its ester, which may be obtained by the hydroforrnylation of an ester of oleic acid using rhodium carbonyl or cobalt carbonyl catalyst, by subjecting the 9(10) formylstearic acid to Strecker reaction or hydantoin formation reaction and hydrolyzing the product in the presence of a strong acid or base.

9( l0)-Formylstearic acid or its lower alkyl ester such as the methyl, ethyl and propyl ester, a source of cyanide ions (hydrogen cyanide, an alkali metal cyanide, or ammonium cyanide) and a source of ammonium ions (ammonia, ammonium hydroxide, ammonium chloride or ammonium cyanide) are heated with or without a source of carbonate ions (carbon dioxide gas, ammonium carbonate, an alkali metal carbonate, or an alkali metal bicarbonate) to a temperate of 50-150C under atmospheric or elevated pressure in a water soluble organic solvent containing water. When a dialkyl amine or monoalkylamine is used instead of ammonia, the N-dialkyl-substituted compound or the N-monoalkyl-substituted compound is obtained.

As the starting compound, the lower alkyl ester such as methyl ester is desirable and it is recommended to mix a solution of the ester in a water soluble solvent such as methanol, ethanol, dioxane, glycerol, ethylene glycol, isopropanol or n-propanol, preferably methanol or ethanol,- with an aqueous solution of the salts which are the secondary materials.

A suitable volume ratio of the organic solvent to water is 1:5 to 5:1 and the solvent mixture is used in an amount to make the concentration of the starting compound about O. l-3 moles/ 1.

Other known methods for converting an aldehyde to the corresponding a-amino acid or a N-alkyl substituted a-amino acid; can also be employed.

After the Strecker or hydantoin formation reaction, the aminonitrile, N-alkyl substituted aminonitrile or hydantoin derivative in the reaction mixture is hydrolyzed by adding a strong acid such as hydrochloric acid or sulfuric acid, or a strong base such as sodium, potassium, calcium or barium hydroxide to the reaction mixture and heating to, about C. for several hours under atmospheric pressure, or about l50-250 C. for up to 40 minutes under an elevated pressure. When an ester of 9(10)-formylstearic acid is used as a starting compound, the ester moiety of the compound is hydrolyzed simultaneously to give the same compound as obtained from the free acid as a starting compound. Although the hydrolysis can be carried out after separating the intermediate aminonitrile, N-alkyl-substituted aminonitrile or hydantoin derivative from the reaction mixture, it is advantageous to perform the hydrolysis in reaction mixture without the separation of the intermediate.

When the product is a free amino acid, the product can be easily isolated from the hydrolysis mixture by removing the organic solvent, adding water to the residual mixture, adjusting the pH of the solution to 3- 4, whereby the product is precipitated as white flakes, and filtering the. When the product an N-alkyl-substituted amino acid, the product can be separated from other substances on the basis of the solubility difference in organic solvents.

The isolation of the product is sometimes difficult and the product is obtained as a viscous coagulum when the purity of the starting compound is low. In such a case, the product can be purified by dissolving the coagulum in one normal aqueous sodium hydroxide, and making the solution weakly acidic with hydrochloric acid to precipitate the product, and repeating this procedure several times. The purification can also be achieved by dissolving the coagulum in an organic solvent such as ethanol, and adding a non-solvent such as benzene to precipitate the product.

According to the method of this invention, the desired product is obtained in a high yield from an inexpensive material, which is derived from soybean oil by an easy operation.

EXAMPLE 1 A mixture of 65.2 g of methyl 9( l)-formylstearate (Purity 94.8 percent; see Example 7), 19.6 g of sodium cyanide, 76.8 g of ammonium carbonate, 250 ml of water and 1 liter of ethanol was heated to 100 C. for 7 hours in a 2 liter autoclave. After cooling the, a solution of 100 g of sodium hydroxide in 250 ml of water was added and the mixture was heated to 200 C. for 30 minutes, cooled, and concentrated to a semisolid material which was then dissolved in water. To the solution, hydrochloric acid was gradually added. When the pH became 7, the whole solution became a translucent gel which was further converted to a mixture of white flakes and transparent liquid at pH 3-4. The flakes were separated by filtration and washed repeatedly with water to remove sodium chloride. The flakes were air-dried, then dried in a vacuum, and consisted of 61.3 g of 2-aminoeicosanedioic acid. (Yield 90.5 percent) Melting point: l48l50 C.

Solubility: Soluble in aqueous inorganic acids and alkali, in methanol, ethanol and acetic acid. Hardly soluble in chloroform. Insoluble in acetone, ether, benzene and cyclohexane. When the concentrated solution prepared by dissolving the compound in hot methanol or ethanol is cooled, it gels. in methyl oleate or methyl linoleate, the compound is insoluble at 120 C, but dissolves above 160 C. and does not crystallize upon cooling to room temperature In soybean oil, the compound is hardly soluble at 150 C., but soluble at 200 C. Paper chromatography:

Rf value; 1.0 (Solvent A or B) 0.6 (Solvent C) Solvent A: Butanol-Acetic acid'Water (4: l :1 by

vol.)

Solvent B: Phenol-Water (3:1 by vol.) Solvent C: Butanol-Methylethyl ketone'Ammonia-Water (5:3: 1:1 by vol.) A blue-violet spot similar to that of alanine is developed by treatment with ninhydrin.

Thin layer chromatography:

Rf value; 0.01 (Solvent D) 0.06 (Solvent E) 0.02 (Solvent F) Temp. pH 22C 7.8 35C 7.6

Elementary analysis:

C H N% Calculated for C l-5N0, 67.19 1 1.00 3.92 Found 67.13 11.17 3.92

EXAMPLE 2 20 Ml of water, 12.5 g of sodium bisulfite and 32.6 g of methyl 9(l0)-formylstearate were stirred for 30 minutes. Then, 6.45 g of percent aqueous solution of ethylamine was added dropwise. After stirring for further 30 minutes, 5 g of sodium cyanide was added all at once and the mixture was stirred for further 30 minutes.

To the reaction mixture, ml of water was added to dissolve inorganic precipitates, and the solution was extracted with ether. The extract was evaporated in a vacuum to 19 g. A mixture of the concentrate, 20 g of sodium hydroxide, 15 ml of water and 15 ml of methanol was heated to 200 C. for 10 minutes in a 100 ml autoclave. The reaction mixture was dissolved in water. The pH of the aqueous solution was adjusted to 3-4 with hydrochloric acid and the solution was extracted with ether. The extract was dried with anhydrous magnesium sulfate and filtered. The filtrate when evaporated in a vacuum at room temperature, yielded 16 g of N-ethyl-2aminoeicosanedioic acid as an oily substance.

Solidifying temperature: 35 40C a Color development by ninhydrin: None Thin-layer chromatography:

Rf value; 88 (Solvent D) 0. 0.81 (Solvent E) 0.37 (Solvent F) um N-ethyl-2-aminoeicosanedioate:

Temp. pH 22C 8. 1 35C 8.0

EXAMPLE 3 A mixture of 6.52 g of methyl 9( l0)-formylstearate, 1.96 g of sodium cyanide, 12.8 ml of 70 percent aqueous solution of ethylamine, 15 ml of methanol, 10 ml of water and 2.4 g of dry ice was heated to C. for 1 hour with stirring in a 100 ml autoclave. After cooling a solution of 10 g of sodium hydroxide in 25 ml water was added and the mixture was further heated to 200 C. for 15 minutes. Then, the reaction mixture was worked up as described in Example 2 to obtain 5 g of N-ethyl-2- aminoeicosanedioic acid.

EXAMPLE 4 A mixture of 13.04 g of 9( l0)-formylstearate, 3.92 g of sodium cyanide, 31 ml of 40 wt. percent aqueous methylamine, 5 g of dry ice, 20 ml of methanol and 30 ml of water was heated to 120 C. for one hour in a 300 ml autoclave. After cooling, g of sodium hydroxide was added, and the mixture was heated to 200 C. for minutes and further treated as in Example 2 to yield 12.0 g of faint yellow oily N-methyl-Z-aminoeicosanedioic acid.

Thin-layer chromatography: Rf value; 0.42 (Solvent Solubility: Similar to N-ethyI-Z-aminoeicosanedioic acid.

EXAMPLE 5 In a 2-liter autoclave, 600 ml of an ethanol solution containing 163 g of methyl 9( l0)-formylstearate (Purity 99.5 percent) and 400 ml of an aqueous solution of 1.5 moles/ 1 hydrogen cyanide, and, 12 moles/ 1 ammonia were heated to 120 C. for 5 minutes. After cooling, 100 g of sodium hydroxide was added and the mixture was heated to 200 C. for 30 minutes to hydrolyze the intermediate formed. The hydrolyzate was worked up as in Example 1 to 152 g of 2-aminoeicasanedioic acid. (Yield 85 percent) EXAMPLE 6 The procedure of Example 3 was repeated, but 600 ml of an aqueous solution containing 1.0 mole/l hydrogen cyanide and 6.7 moles/ l dimethylamine was used instead of the ammoniacal solution and N.N- dimethy1-2-aminoeicosanedioic acid was obtained.

Thin-layer chromatography:

Rf; 0.52 (Ethanol:Acetic Acid 95:5 by volume) 0.57 (Methanol:Chloroform 1:1 by volume) Solubility: Soluble in methanol, ethanol, tetrahydrofuran and aqueous alkaline solutions. Hardly soluble in hexane, benzene, ethyl ether and water.

EXAMPLE 7 Benzene was added to 297.3 g of methyl oleate containing, as impurities, 5% linoleic acid and traces of methyl stearate and methyl linoleate and 150 mg of rhodium oxide to make the volume of the mixture 1 liter. The mixture was placed in a 1.6-liter auto-clave and equal volumes of carbon monoxide and hydrogen gas were admitted to the autoclave until the pressure reached 200 kg/cm whereupon the contents of the autoclave were heated to ll0-130 C. for 30 minutes with stirring. After cooling, the mixture was partly evaporated to recover the solvent. The concentrate was fractionated in a vacuum to obtain 301.4 g of a distillate of boiling point of 204221 C. (3-4 mmHg), which was further fractionally distilled with a 30 cm distillation column to obtain the following fractions:

lst fraction l64-l901.0-1.2 mmHg) 10 g 2nd fraction (l92l821.20.5 mmHg) 171.4 g (Purity measured by gas chromatography. 94.8%) 3rd fraction (l82l760.5-O.25 mmHg) 108.1 g (Purity measured by gas chromatography. 99.5%)

The 2.4-dinitrophenylhydrazone of the methyl-9( l0) formylstearate so obtained melted at 7376 C.

Elementary analysis:

C H N% Calculated for C H N O 61.63 8.36 l 1.06 Found 61.84 8.32 10.75

EXAMPLE 8 To 5.1 g of Z-aminoeicosanedioic acid in ml of methanol, ml of methanol saturated with hydrogen chloride were added and the mixture was refluxed for 45 minutes. After the reaction, excess hydrogen chloride and methanol were removed by vacuum distillation. The oily residue was neutralized with 10 percent methanollic sodium hydroxide. The sodium chloride precipitated was removed by filtration and ethyl ether was added to the filtrate to precipitate a white translucent substance which was reprecipitated from methanol-ether, and washed with petroleum ether to remove the diester formed by a side reaction. 3.0 G of Elementary analysis:

c H N% Calculated for c,,1-1,,o,N 67.88 1 1.12 3.77 Found 67.65 11.13 3.91

EXAMPLE 9 20 Parts of monosodium 2-aminoeicosanedioate and monosodium N-ethyl-2-aminoeicosanedioate were each dissolved in 80 parts of water to obtain transparent liquid detergents. The detergents were subjected to comparison tests as described below in which the compared materials are identified as follows:

Sample A: Monosodium-Z-aminoeicosanedioate B: Monosodium N-ethyl-2- aminoeicosanedioate C: Neat soap D: N-lauroyl sarcosinate E: Sodium laurylsulfate Concentration of the sample; 0.25 wt.% Temperature; 40C

1. Foaming Ability:

According to the method of JIS (Japanese Industrial Standard) K3362-1955, foaming ability (height of foam) was measured.

Height of Foam (mm) Sample afier 0 min. 5 min. 10 min. 20 min. 30 min.

A 114 37 3 B 69 19 11 6 C 158 158 154 154 D 130 115 110 100 98 E 205 179 177 177 ii. Lime Soap Dispersing Power:

The minimum amount of the sample detergent necessary for completely dispersing calcium oleate was measured by the method described in the Journal of the American Oil Chemists Society, 27, 90 1950).

Weight of the detergent to disperse lime soap (2.)

Lime soap dispersing power percent:- Weight ofsodium olente (g) iii. Penetration Power According to the method of 118 K3362, a test cloth was floated on the surface of 500 ml of an aqueous sample solution in a measuring cylinder of 500 ml capacity by means of a wire ring, and the time till the test cloth began to sink was measured. The temperature of the sample solution was 40 C.

The test cloth: Felt (11S 20 ounce) 3 X 18 cm, whose moisture was controlled by storage in a desiccator containing ammonium nitrate for 12 hours, prior to use.

The following penetration power values are averages of ten tests.

above 30 minutes iv. Emulsifying Power:

In a stoppered test tube (10 mm diameter, 390 mm height), 10 ml of an aqueous sample solution and 10 ml of toluene were allowed to stand for 20 minutes in a thermostat of 40 C. Then the test tube was inverted 30 times, being returned to the starting position each time. The test tube was put again in the thennostat and the condition of the mixture (separation of the two layers and height of water layer) was observed. The percentage of toluene emulsified by the sample detergent at various times after the last inversion was as follows.

Emulsified amount of toluene (96) Sample 1 min. 3 min. 5 min. min. min. min. 30 min.

A 82 66 44 33 27 23 I8 D 55 30 21 22 10 7 6 C 8O 5] 37 26 2O l7 12 v. Relative Interfacial Tension According to the method of 1 IS K-3304 and K-3362,

the number of drops (N) of kerosene (3 ml) discharged from a stalagmometer 120 mm height, 0.5 mm diameter) into 150 ml of 0.25 wt. percent or 0.05 wt. percent aqueous sample solution in a vessel (61 mm diameter, 122 mm height) was determined. The discharge rate of the kerosene was 16 i 2 drops per minute and the temperature was 40 C.

Similarly, the number of drops (N of kerosene (3 ml) into 150 ml water was determined.

Relative lnterfacial Tension =(N,,/N)

Sample Relative lnterfacial Tension 0.l98(0.25 wt.%), 0.09(pH 7.0, 0. l59(0.25 wt.%)

below 0.l(0.25 wt.%), 0.45(0.05 wt.%) below O.l(0.25 wt.%), 0.63(0.05 wt.%) below 0.l(0.25 wt.%), 0.28(0.05 wt.%)

Relative surface tension =(N /N) Sample Relative surface tension A 0.58l C 0.344 D 0.629

vii. Detergency:

Soiled fabric; Cotton fabric, 5 X 5 cm Soil composition;

Substance Myristic acid Oleic acid Tristearin Triolein Cholesterol Cholesterol stearate Parafl'in Squalene burned clay Carbon black The soil mixture was rubbed on the fabric by hand more than 50 times to reduce the light reflectance to 40-44 percent.

Washing device: Abstergent tester Kamishima Seisakusho Ltd. Japan.

Washing method: Six sheets of the soiled fabric were put into a cleaning bath consisting of 900 ml of 0.04 wt. percent aqueous solution (pH 10) of a detergent with or without calcium carbonate, together with unsoiled fabric (5 X 10 cm) to adjust the bath ratio to 50 and washed for 12 minutes at 100 r.p.m. at 25 C. After washing, the fabrics were rinsed with water twice for one minute.

made by Calculation of detersive efficiency;

Detersive efficiency X 100 R0 RI R Reflectance of original fabric prior to soiling R Reflectance of soiled fabric prior to washing R: Reflectance of tested fabric after washing Hardness Detergent Detersive efficiency Measurement method; Nord et al.s method (Journal of the Agricultural and Chemical Society of Japan, A 51.5 36, 860(1962)) 0 F 68 A 52 100 F 42,5 Sample Remaining activity of lipase A 58 A 100 300 F 49 F 60 A 57 water only I00 400 F 40 xi. Krafit point:

An aqueous solution of each sample (concentration;

50 millimoles/liter) was cooled and the temperature at which the solution became solid was measured.

Hardness: CaCO 1 ppm hardness l Detergent F: sodium n-dodecylbenzenesulfonate viii. Stabilization ability for protease:

Concentration of sample; 0.2 wt.% aqueous solution Sam le Krafit oint C Protease: alkaline protease, Asterase (Trade p p Mark), Activity 49.00 ;i/ g; Concentration in sam- A below 0 ple solution, 0.06 wt.% A35 55 Time: 30 minutes L-LGS 38 Temperature: 50C Measurement method; Anson 5 method pH of sample solution; 9.5

L-LGSodium N-lauroyl-L-glutamate xii. Irritation of Skin: Sam le Remiaiqillgei fi y of sy i z Patch tests were carried out on the inner arm surface f 82 79 of 20 women and 20 men E 40 Patch time: 24 hours ii Patch: 30 mm X 30 mm four fold gauze wetted with the following sample solutions: ABS: Sodium alkybenzene sulfonate 20 percent aqueous solution ofA ix. Stabilization ability for amylase: 10 percent aqueous sollut.lon :3 Concentration of sample; 0.2 wt. percent aqueous 10 0 Solution D Aqueous solution of sodium dodecylbenzenesul- Amylase; spitase (Trade Mark), Activity; fonate 15 wt. percent) and sodium salt of coconut 7,000 u/g. Concentration in sample solution, 0.18 l Sulfate? (5 percent) wt. percent D D diluted with water to one-half concentration. Temperature; 50 C. Time; 30 minutes 40 Tested persons suffering Sample strong weak no p of sample Solution; irritation irritation irritation Measurement method; Modification of Wohlgemuths method: One unit was defined as the amylase activity which decomposes completely 1 2; g ml of 0.65 wt. percent aqueous water-soluble g= 2 8 starch solution at 40 C. for 10 minutes. The 21 19 0 complete decomposition was determined by measuring the absorbancy at 660 mp. of a solution colored by starch-iodine reaction and it was EXAMPLE 1O deemed that the decomposition was complete Sodium dodecylbenzenesulfonate 10 parts when the absorbancy becfime 0300- Monopotassium 2-aminoeicosanedicarboxylate 5 parts Diethanolamide of coconut fatty acid 5 parts Sample Remaining activity of amylase P f a ll amount were dissolved in parts of water with stirring to ob- A tain a liquid detergent. The detergent showed good g, only 8 foaming ability and detergency. In patch tests similar to Example 9 (x), 31 of 40 persons tested did not suffer irritation. x. Stabilization activity for lipase: 6O EXAMPLE 1 1 Concentration of sample; 0.2 wt. percent Lipase; Lipase MY (Trade i i 20,000 A mixture of 70 parts of neat soap chips and 15 parts u/g Concentration in ample olution wt pep Of monosodium 2-aminoeicosanedioate W38 kneaded cent 65 with water and the mixture was made into bar soap on Temperature; 50 C. conventional equipment for preparing milled soap. The Time; 30 minutes bar soap obtained showed proper foaming ability and pH; 7.0 solubility by rubbing. The lime soap dispersing power of the soap was 200%. It was also found that the stability in hard water was improved by the addition of monosodium 2aminoeicosanedioate.

EXAMPLE 1 l Monopotassium Z-aminoeicosanedioate 15 parts Triethanolamine salt of Z-aminoeicosanedioate acid parts Laurie acid diethanolamide 5 parts Glycerol 3 pans were added to 72 parts of water and dissolved with stirring to obtain a transparent liquid shampoo.

EXAMPLE 1 l Monosodium N-methyl-2-aminoeicosanedioate parts Monosodium N,N-dimelhyl-2-amin0eicosanedioate 5 parts Coconut fatty acid diethanolamide l0 pans Glycerol 3 parts were added to 67 parts of water and dissolved with stirring to obtain a transparent shampoo.

EXAMPLE 12 Sodium dodecylbenzenesulfonate I00 pans Monosodium Z-aminoeicrxsunedioate [0 parts Sodium polyphosphate 100 parts Carboxymethyl cellulose 3 parts Glauber's salt 450 parts or a mono-lower-alkyl ester or a water soluble salt of said dicarboxylic acid, in said formula, n being 7 or 8, and R, and R being hydrogen or lower alkyl.

2. A compound as set forth in claim 1, which is an alkali metal or ammonium salt of said acid. 

2. A compound as set forth in claim 1, which is an alkali metal or ammonium salt of said acid. 